The Distortion Analysis Of Box Girder

The box girder is a kind of sectional form adopted extensively in the bridge at present, there is fine structure that receives strength performance , but thin wall structure torsion analysing comparatively complicated, this paper introduced the box girder torsion theory of nothing section distortion and consider section distortion bend over broad sense calculus of V.Z.Vlasov. it also introduced the thin wall finite element theory with distorted and undistorted section, and work out corresponding finite element program, this program is very applicable to the torsional analysis of the turn simple one section thin wall straight pole , have the higher precision of calculation.Turn as to the torsion analysis of complicated continuous beam, it need the space analysis with the general finite element program. This paper regards Nenjiang highway bridge model test of Qiqihar as the research object, adopt finite element program ANSYS to emulate the test model, at the different load operation ,it compare the calculate value to test value of the shear-lag effect and torsion effect, have made the comparatively ideal result, have proved to complicated turning the feasibility of analysing the space into the continuous case roof beam of section with shell element SHELL63 in ANSYS. Based on this, it discussed influence degree of horizontal density of diaphragm to the distortion of the continuous girder bridge at the different load, think through computational analysis , the horizontal diaphragm can reduce the distortion effect of the continuous girder bridge, set up the diaphragm nearby greater distortion stress in the reduction that it can be effective supports the place and steps specially while supporting the place and stepping, but set up a fairly large number of horizontal diaphragm, it is very difficult to reduce the continuous distortion effect to neglected degree, so must consider the influence of distortion when we analyse the continuous girder bridge. Finally, at the certain diaphragm idensity, have made brief analysis in impact on distortion effect of change of the diaphragm thickness in the middle, the change of the horizontal thickness of diaphragm has a little effect on distortion effect, this conclusion is unanimous with Japanese scholar. This paper' conclusion would be help to the design and construction of the continuous girder bridge.